Hand-Held Portable Backscatter Inspection System

ABSTRACT

The present specification describes a compact, hand-held probe or device that uses the principle of X-ray backscatter to provide immediate feedback to an operator about the presence of scattering and absorbing materials, items or objects behind concealing barriers irradiated by ionizing radiation, such as X-rays. Feedback is provided in the form of a changing audible tone whereby the pitch or frequency of the tone varies depending on the type of scattering material, item or object. Additionally or alternatively, the operator obtains a visual scan image on a screen by scanning the beam around a suspect area or anomaly.

CROSS-REFERENCE

The present application is a continuation application of U.S. Pat.Application No. 17/126,342, entitled “Hand-Held Portable BackscatterInspection System” and filed on Dec. 18, 2020, which is a continuationapplication of U.S. Pat. Application No. 16/199,531, of the same title,filed on Nov. 26, 2018, and issued as U.S. Pat. No. 10,901,113 on Jan.26, 2021, which is a continuation application of U.S. Pat. ApplicationNo. 15/074,787, of the same title, filed on Mar. 18, 2016, and issued asU.S. Pat. Application No. 10,168,445 on Jan. 1, 2019, which relies onU.S. Pat. Provisional Application No. 62/136,299, entitled “HandheldPortable Backscatter Inspection System” and filed on Mar. 20, 2015, forpriority.

U.S. Pat. Application No. 15/074,787 also relies on U.S. Pat.Provisional Application No. 62/136,305, entitled “Handheld PortableBackscatter Inspection System” and filed on Mar. 20, 2015, for priority.

U.S. Pat. Application No. 15/074,787 also relies on U.S. Pat.Provisional Application No. 62/136,315, entitled “Handheld PortableBackscatter Inspection System” and filed on Mar. 20, 2015, for priority.

U.S. Pat. Application No. 15/074,787 also relies on U.S. Pat.Provisional Application No. 62/136,322, entitled “Handheld PortableBackscatter Inspection System” and filed on Mar. 20, 2015, for priority.

U.S. Pat. Application No. 15/074,787 also relies on U.S. Pat.Provisional Application No. 62/136,362, entitled “Handheld PortableBackscatter Inspection System” and filed on Mar. 20, 2015, for priority.

All of the above-mentioned applications are herein incorporated byreference in their entirety.

FIELD

The present specification generally relates to a portable backscatterscanning system, and in particular, relates to a system which can becarried by an operator by hand to sites of inspection, includingconfined locations, and subsequently used to scan for detection ofconcealed materials and objects.

BACKGROUND

Materials, such as narcotics, explosives or currency, and objects, suchas weapons or people, are concealed within or behind barriers with theintention that the materials or objects remain undetected by routine ortargeted security checks.

Today, scanning devices are well known which use a variety of sensingmethods to detect concealed materials and objects. These scanningdevices include transmission X-ray imaging systems, Comptonscatter-based backscatter imaging systems, chemical sniffing tracedetection equipment, thermal imaging camera systems and so on. Suchscanning devices may be used alone or in combination to provide acomprehensive level of security. However, such devices tend either to belarge and expensive (e.g. transmission X-ray imaging systems) orinsensitive to carefully hidden materials (e.g. trace detectionequipment and camera systems) which means that their utility isrestricted to certain high throughput situations such as sea ports andland borders, airport checkpoints and so on.

Therefore, what is needed is a compact, light-weight, portable andhand-held system or device that can be maneuvered to reach relativelyinaccessible locations and scan behind concealing barriers that areotherwise opaque against chemical and optical probes. Such a system ordevice should be able to provide immediate feedback if a suspiciousmaterial, object or anomaly is detected and should allow an operator toobtain information about the concealed material or object, for threatresolution, without the need to breach the concealing barrier.

SUMMARY

In some embodiments, the present specification discloses a method forscanning an object by projecting a shaped X-ray beam from a hand-heldimaging device, where the device includes a housing enclosing an X-raytube that emits the shaped X-ray beam, a plurality of detectors forgenerating scan data corresponding to a plurality of detected X-raybeams scattered from the object, a processor in communication with agyroscope and an accelerometer, and an acquisition system incommunication with a speaker, a display, the processor and the pluralityof detectors. In some embodiments, the method includes using theprocessor for calculating a plurality of active pixels corresponding toa location of interaction of the shaped X-ray beam on the object; usingthe processor for calculating a time duration, at each of said pluralityof active pixels, for which the shaped X-ray beam is present over eachof said plurality of active pixels; and using the processor to generatean image, on said display, of the object after correcting the scan data,at each of said plurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is a pencil beam.

In some embodiments, the shaped X-ray beam is a cone beam.

In some embodiments, the shaped X-ray beam is a fan beam.

In some embodiments, the shaped X-ray beam is a single-axis rotatingbeam.

In some embodiments, the shaped X-ray beam is a dual-axis rotating beam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to calculating said plurality ofactive pixels, calculating said time duration and generating said image.Optionally, the anomaly is identified based on a change in audible tonegenerated by the speaker. Optionally, the processor and speaker areadapted to generate said audible tone such that a pitch or frequency ofsaid audible tone varies in proportion to said scan data.

Optionally, upon identification of said at least one anomaly, thehand-held imaging device is swept to scan the object using a finescanning pattern for calculating said plurality of active pixels,calculating said time duration and generating said image.

In some embodiments, the processor receives second data which isgenerated by the accelerometer and is indicative of a movement of theshaped X-ray beam being projected on the object. In some embodiments,the method includes based on said second data: using the processor forcalculating a plurality of active pixels corresponding to a new locationof interaction of the shaped X-ray beam on the object; using theprocessor for calculating a time duration, at each of said plurality ofactive pixels, for which the shaped X-ray beam is present over each ofsaid plurality of active pixels; and using the processor for generatingan updated image, on said display, of the object after correcting thescan data, at each of said plurality of active pixels, using said timeduration.

In some embodiments, the new location is associated with an updatedfirst data generated by the gyroscope, and wherein said updated firstdata is indicative of a new direction of the shaped X-ray beam beingprojected on the object.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration ranging between 0.01 ms and 100 ms.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the location is associated with a first datagenerated by the gyroscope, and wherein said first data is indicative ofa direction of the shaped X-ray beam being projected on the object.

In some embodiments, the present specification discloses a system for ahand-held imaging device for scanning an object by projecting a shapedX-ray beam. In some embodiments, the system includes a housing having acentral longitudinal axis and including: a plurality of detectors forgenerating scan data corresponding to a plurality of detected X-raybeams scattered from the object; a gyroscope; an accelerometer; anacquisition system in communication with a display and said plurality ofdetectors; and a processor in communication with said gyroscope, saidaccelerometer and said acquisition system. In some embodiments, saidprocessor is configured for: calculating a plurality of active pixelscorresponding to a location of interaction of the shaped X-ray beam onthe object; calculating a time duration, at each of said plurality ofactive pixels, for which the shaped X-ray beam is present over each ofsaid plurality of active pixels; and generating an image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is a pencil beam.

In some embodiments, the shaped X-ray beam is a cone beam.

In some embodiments, the shaped X-ray beam is a fan beam.

In some embodiments, the shaped X-ray beam is a single-axis rotatingbeam.

In some embodiments, the shaped X-ray beam is a dual-axis rotating beam.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a trapezoidal prism culminating in saidrear surface.

Optionally, the shaped X-ray beam emerges through an opening at a centerof said front surface in a direction substantially perpendicular to saidfront surface. Optionally, the plurality of detectors are positionedadjacent to and behind said front surface surrounding said opening atthe center of said front surface.

In some embodiments, the system includes a speaker, wherein saidprocessor and speaker are adapted to generate an audible tone such thata pitch or frequency of said audible tone varies in proportion to saidscan data.

Optionally, the housing further comprises a plurality of vanes forcollimating a plurality of X-ray beams scattered from the object.Optionally, said plurality of vanes are arranged in planes that aresubstantially parallel to each other. Optionally, said plurality ofvanes are arranged in planes that are substantially parallel to eachother and in a direction substantially perpendicular to an orientationof a plane of a fan beam. Optionally, said plurality of vanes isarranged in planes in a substantially diverging orientation with respectto each other. Optionally, said plurality of vanes is arranged in planesin a substantially converging orientation with respect to each other.

Optionally, the housing further comprises a grid of a plurality ofcollimator elements for collimating a plurality of X-ray beams scatteredfrom the object. Still optionally, said grid comprises first and secondsets of a plurality of combs, each of said plurality of combs havingteeth, wherein the teeth of said first set of combs in a first directioninterlock with the teeth of said second set of combs in a seconddirection, and wherein said second direction is substantially orthogonalto said first direction. Optionally, said teeth are arranged in planardirections substantially parallel to an orientation of said shaped X-raybeam. Still optionally, said teeth are arranged in planar directionssubstantially parallel to each other. Optionally, said teeth arearranged in planar orientations that are substantially divergent withrespect to each other. Optionally, said teeth are arranged in planarorientations that are substantially convergent with respect to eachother. Optionally, each of said plurality of detectors maps to an areaon the object, wherein said area is defined by a solid angle of a conebeam and an acceptance angle of each of said plurality of collimatorelements.

Optionally, the housing further comprises a first rotating collimatorhaving a first transmission pattern and a second rotating collimatorhaving a second transmission pattern, said first and second transmissionpatterns defining said shaped X-ray beam. Optionally, said firsttransmission pattern defines a radial position of a pencil beam whilesaid second transmission pattern defines an azimuthal angle of saidpencil beam. Optionally, said first and second collimators rotate inlock step with each other, and wherein said first collimator rotates ata first speed while said second collimator rotates at a second speed.Optionally, said second speed is greater than said first speed.Optionally, said first and second collimators are substantially circulardisks having differing radii. Optionally, said first and secondcollimators are substantially circular disks having equal radii.Optionally, said first transmission pattern is a slit extending in aspirally curved configuration from a point proximate to a center pointof said first collimator to a point proximate to a circumference of saidfirst collimator, and wherein said second transmission pattern is a slitextending radially from a point proximate to a center of said secondcollimator to a point proximate to a circumference of said secondcollimator.

Optionally, said housing further comprises a rotating collimator havinga transmission pattern defining the shaped X-ray beam, the rotatingcollimator supported and partially surrounded by an oscillating shapedcradle. Optionally, said collimator rotates at a speed ranging between100 to 5000 RPM. Optionally, said collimator rotates at a speed of 2000RPM. Optionally, said rotating collimator causes said shaped X-ray beamto sweep a trajectory in a substantially vertical plane such that afocal spot of said shaped X-ray beam is in a plane of said rotatingcollimator and on a central longitudinal axis of said housing, andwherein said oscillating shaped cradle causes said shaped X-ray beam tosweep left to right, repeatedly, over said substantially vertical plane.Optionally, said collimator is a substantially circular disk having afirst radius while said shaped cradle is substantially semi-circularhaving a second radius, and wherein said second radius is greater thansaid first radius. Optionally, said collimator is a substantiallycircular disk having a radius while said shaped cradle is substantially‘U’ or ‘C’ shaped. Optionally, said transmission pattern is an openingat a point between a center and a circumference of said collimator, andwherein said rotating and oscillating movements together cause saidshaped X-ray beam to move in a raster pattern over a two dimensionalarea of the object.

In some embodiments, the present specification is directed toward amethod of scanning an object by projecting a shaped X-ray beam from ahand-held imaging device. In some embodiments, the device includes ahousing enclosing an X-ray tube that emits the shaped X-ray beam, aplurality of detectors for generating scan data corresponding to aplurality of detected X-ray beams scattered from the object, a processorin communication with a gyroscope and an accelerometer, and anacquisition system in communication with a speaker, a display, saidprocessor and said plurality of detectors. In some embodiments, themethod incudes receiving first data by the processor, wherein said firstdata is generated by the gyroscope and is indicative of a direction ofthe shaped X-ray beam being projected on the object; using the processorfor calculating a plurality of active pixels corresponding to a locationof interaction of the shaped X-ray beam on the object, wherein saidlocation is associated with said first data; using the processor forcalculating a time duration, at each of said plurality of active pixels,for which the shaped X-ray beam is present over each of said pluralityof active pixels; and using the processor for generating an image, onsaid display, of the object after correcting the scan data, at each ofsaid plurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to receiving said first data,calculating said plurality of active pixels, calculating said timeduration and generating said image. Optionally, the anomaly isidentified based on a change in audible tone generated by the speaker.Still optionally, a pitch or frequency of said audible tone isproportional to said generated scan data.

Optionally, upon identification of said at least one anomaly, thehand-held imaging device is swept to scan the object using a finescanning pattern for receiving said first data, calculating saidplurality of active pixels, calculating said time duration andgenerating said image. Optionally, the method further includes receivingsecond data by the processor, wherein said second data is generated bythe accelerometer and is indicative of a movement of the shaped X-raybeam being projected on the object. In some embodiments, based on saidsecond data, the method includes receiving updated first data by theprocessor indicative of a new direction of the shaped X-ray beam beingprojected on the object; using the processor for calculating a pluralityof active pixels corresponding to a location of interaction of theshaped X-ray beam on the object, wherein said location is associatedwith said updated first data indicative of the new direction; using theprocessor for calculating a time duration, at each of said plurality ofactive pixels, for which the shaped X-ray beam is present over each ofsaid plurality of active pixels; and using the processor for generatingan updated image, on said display, of the object after correcting thescan data, at each of said plurality of active pixels, using said timeduration.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration ranging between 0.01 ms and 100 ms.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the present specification is directed towards asystem for a hand-held imaging device for scanning an object byprojecting a shaped X-ray beam, where the device includes a housinghaving a central longitudinal axis. In some embodiments, the housingincludes a plurality of detectors for generating scan data correspondingto a plurality of detected X-ray beams scattered from the object; agyroscope; an accelerometer; an acquisition system in communication witha speaker, a display and said plurality of detectors; and a processor incommunication with said gyroscope, said accelerometer and saidacquisition system. In some embodiments, said processor is configuredfor receiving first data generated by the gyroscope and indicative of adirection of the shaped X-ray beam being projected on the object;calculating a plurality of active pixels corresponding to a location ofinteraction of the shaped X-ray beam on the object, wherein saidlocation is associated with said first data; calculating a timeduration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and generating an image, on said display, of the object aftercorrecting the scan data, at each of said plurality of active pixels,using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a second cuboid culminating in said rearsurface. Optionally, the shaped X-ray beam emerges through an opening ata center of said front surface in a direction substantiallyperpendicular to said front surface. Optionally, the plurality ofdetectors are positioned adjacent to and behind said front surfacesurrounding said opening at the center of said front surface.Optionally, there are four sets of detectors.

In some embodiments, the present specification is directed towards amethod of scanning an object by projecting a shaped X-ray beam from ahand-held imaging device. In some embodiments, the device includes ahousing enclosing an X-ray tube that emits the shaped X-ray beam, aplurality of vanes for collimating a plurality of X-ray beams scatteredfrom the object, a plurality of detectors for generating scan datacorresponding to the plurality of collimated X-ray beams detected bysaid plurality of detectors, a processor in communication with agyroscope and an accelerometer, and an acquisition system incommunication with a speaker, a display, said processor and saidplurality of detectors. In some embodiments, the method includes usingthe processor for calculating a plurality of active pixels correspondingto a location of interaction of the shaped X-ray beam on the object;using the processor for calculating a time duration, at each of saidplurality of active pixels, for which the shaped X-ray beam is presentover each of said plurality of active pixels; and using the processorfor generating an image, on said display, of the object after correctingthe scan data, at each of said plurality of active pixels, using saidtime duration.

In some embodiments, the shaped X-ray beam is in the form of a fan beam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to calculating said plurality ofactive pixels, calculating said time duration and generating said image.Optionally, the one anomaly is identified based on a change in audibletone generated by the speaker. Still optionally, a pitch or frequency ofsaid audible tone is proportional to said generated scan data.Optionally, upon identification of said at least one anomaly, thehand-held imaging device is swept to scan the object using a finescanning pattern for calculating said plurality of active pixels,calculating said time duration and generating said image. Stilloptionally, the method further includes receiving second data by theprocessor, wherein said second data is generated by the accelerometerand is indicative of a movement of the shaped X-ray beam being projectedon the object and wherein based on said second data using the processorfor calculating a plurality of active pixels corresponding to a newlocation of interaction of the shaped X-ray beam on the object; usingthe processor for calculating a time duration, at each of said pluralityof active pixels, for which the shaped X-ray beam is present over eachof said plurality of active pixels; and using the processor forgenerating an updated image, on said display, of the object aftercorrecting the scan data, at each of said plurality of active pixels,using said time duration. Optionally, the new location is associatedwith an updated first data generated by the gyroscope, and wherein saidupdated first data is indicative of a new direction of the shaped X-raybeam being projected on the object.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the location is associated with a first datagenerated by the gyroscope, and wherein said first data is indicative ofa direction of the shaped X-ray beam being projected on the object.

In some embodiments, the present specification discloses a system for ahand-held imaging device for scanning an object by projecting a shapedX-ray beam, where the device includes a housing having a centrallongitudinal axis. In some embodiments, the housing includes a pluralityof vanes for collimating a plurality of X-ray beams scattered from theobject;

a plurality of detectors for generating scan data corresponding to theplurality of collimated X-ray beams detected by said plurality ofdetectors; a gyroscope; an accelerometer; an acquisition system incommunication with a speaker, a display and said plurality of detectors;and a processor in communication with said gyroscope, said accelerometerand said acquisition system. In some embodiments, the processor isconfigured for calculating a plurality of active pixels corresponding toa location of interaction of the shaped X-ray beam on the object;calculating a time duration, at each of said plurality of active pixels,for which the shaped X-ray beam is present over each of said pluralityof active pixels; and generating an image, on said display, of theobject after correcting the scan data, at each of said plurality ofactive pixels, using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a fan beam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to said processor calculating saidplurality of active pixels, calculating said time duration andgenerating said image. Optionally, the anomaly is identified based on achange in audible tone generated by the speaker. Still optionally, apitch or frequency of said audible tone is proportional to saidgenerated scan data. Optionally, upon identification of said at leastone anomaly, the hand-held imaging device is swept to scan the objectusing a fine scanning pattern for calculating said plurality of activepixels, calculating said time duration and generating said image.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a second cuboid culminating in said rearsurface. Optionally, the shaped X-ray beam emerges through an opening ata center of said front surface in a direction substantiallyperpendicular to said front surface. Optionally, the plurality ofdetectors are positioned adjacent to and behind said front surfacesurrounding said opening at the center of said front surface, andwherein said plurality of vanes are positioned in front of saidplurality of detectors and behind said front surface.

In some embodiments, the plurality of detectors include four sets ofdetectors.

In some embodiments, planes of said plurality of vanes are arranged in adirection substantially perpendicular to an orientation of a plane ofsaid fan beam. Optionally, planes of said plurality of vanes arearranged one of substantially parallel to each other, in a substantiallydiverging orientation with respect to each other, and in a substantiallyconverging orientation with respect to each other.

In some embodiments, the present specification discloses a method forscanning an object by projecting a shaped X-ray beam from a hand-heldimaging device. In some embodiments, the device includes a housingenclosing an X-ray tube that emits the shaped X-ray beam, a grid of aplurality of collimator elements for collimating a plurality of X-raybeams scattered from the object, a plurality of detectors for generatingscan data corresponding to the plurality of collimated X-ray beamsdetected by said plurality of detectors, a processor in communicationwith a gyroscope and an accelerometer, and an acquisition system incommunication with a speaker, a display, said processor and saidplurality of detectors. In some embodiments, the method includes usingthe processor for calculating a plurality of active pixels correspondingto a location of interaction of the shaped X-ray beam on the object;using the processor for calculating a time duration, at each of saidplurality of active pixels, for which the shaped X-ray beam is presentover each of said plurality of active pixels; and using the processorfor generating an image, on said display, of the object after correctingthe scan data, at each of said plurality of active pixels, using saidtime duration.

In some embodiments, the shaped X-ray beam is in the form of a conebeam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to calculating said plurality ofactive pixels, calculating said time duration and generating said image.Optionally, the anomaly is identified based on a change in audible tonegenerated by the speaker. Still optionally, a pitch or frequency of saidaudible tone is proportional to said generated scan data. Optionally,upon identification of said at least one anomaly, the hand-held imagingdevice is swept to scan the object using a fine scanning pattern forcalculating said plurality of active pixels, calculating said timeduration and generating said image. Still optionally, the method furtherincludes receiving second data by the processor, wherein said seconddata is generated by the accelerometer and is indicative of a movementof the shaped X-ray beam being projected on the object and wherein basedon said second data the method includes using the processor forcalculating a plurality of active pixels corresponding to a new locationof interaction of the shaped X-ray beam on the object; using theprocessor for calculating a time duration, at each of said plurality ofactive pixels, for which the shaped X-ray beam is present over each ofsaid plurality of active pixels; and using the processor for generatingan updated image, on said display, of the object after correcting thescan data, at each of said plurality of active pixels, using said timeduration. Still optionally, the new location is associated with anupdated first data generated by the gyroscope, and wherein said updatedfirst data is indicative of a new direction of the shaped X-ray beambeing projected on the object.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration ranging between 0.01 ms and 100 ms.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the location is associated with a first datagenerated by the gyroscope, and wherein said first data is indicative ofa direction of the shaped X-ray beam being projected on the object.

In some embodiments, the present specification discloses a system for ahand-held imaging device for scanning an object by projecting a shapedX-ray beam, where the device includes a housing having a centrallongitudinal axis and including a grid of a plurality of collimatorelements for collimating a plurality of X-ray beams scattered from theobject; a plurality of detectors for generating scan data correspondingto the plurality of collimated X-ray beams detected by said plurality ofdetectors; a gyroscope; an accelerometer; an acquisition system incommunication with a speaker, a display and said plurality of detectors;and a processor in communication with said gyroscope, said accelerometerand said acquisition system. In some embodiments, the processor isconfigured for calculating a plurality of active pixels corresponding toa location of interaction of the shaped X-ray beam on the object;calculating a time duration, at each of said plurality of active pixels,for which the shaped X-ray beam is present over each of said pluralityof active pixels; and generating an image, on said display, of theobject after correcting the scan data, at each of said plurality ofactive pixels, using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a conebeam.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a second cuboid culminating in said rearsurface. Optionally, the shaped X-ray beam emerges through an opening ata center of said front surface in a direction substantiallyperpendicular to said front surface. Optionally, the plurality ofdetectors are positioned adjacent to and behind said front surfacesurrounding said opening at the center of said front surface, andwherein said grid is positioned behind said front surface and in frontof said plurality of detectors such that at least one of said pluralityof detectors is present per said collimator element.

In some embodiments, the grid comprises first and second sets of aplurality of combs, each of said plurality of combs having teeth,wherein the teeth of said first set of combs in a first directioninterlock with the teeth of said second set of combs in a seconddirection, and wherein said second direction is substantially orthogonalto said first direction. Optionally, planes of said teeth are arrangedin one of a direction substantially parallel to an orientation of saidshaped X-ray beam, substantially parallel to each other, substantiallydiverging orientation with respect to each other, and substantiallyconverging orientation with respect to each other.

In some embodiments, each of said plurality of detectors maps to an areaon the object, wherein said area is defined by a solid angle of saidcone beam and an acceptance angle of each of said plurality ofcollimator elements.

In some embodiments, the present specification discloses a method forscanning an object by projecting a shaped X-ray beam from a hand-heldimaging device. In some embodiments, the device includes a housingenclosing an X-ray tube that emits the shaped X-ray beam, a firstrotating collimator having a first transmission pattern and a secondrotating collimator having a second transmission pattern, said first andsecond transmission patterns defining said shaped X-ray beam, aplurality of detectors for generating scan data corresponding to aplurality of detected X-ray beams, a processor in communication with agyroscope and an accelerometer, and an acquisition system incommunication with a speaker, a display, said processor and saidplurality of detectors. In some embodiments, the method includes usingthe processor for calculating a plurality of active pixels correspondingto a location of interaction of the shaped X-ray beam on the object;using the processor for calculating a time duration, at each of saidplurality of active pixels, for which the shaped X-ray beam is presentover each of said plurality of active pixels; and using the processorfor generating an image, on said display, of the object after correctingthe scan data, at each of said plurality of active pixels, using saidtime duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam. Optionally, the first transmission pattern defines a radialposition of said pencil beam while said second transmission patterndefines an azimuthal angle of said pencil beam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to calculating said plurality ofactive pixels, calculating said time duration and generating said image.Optionally, the anomaly is identified based on a change in audible tonegenerated by the speaker. Still optionally, a pitch or frequency of saidaudible tone is proportional to said generated scan data. Optionally,upon identification of said at least one anomaly, the hand-held imagingdevice is swept to scan the object using a fine scanning pattern forcalculating said plurality of active pixels, calculating said timeduration and generating said image.

In some embodiments, the method further includes receiving second databy the processor, wherein said second data is generated by theaccelerometer and is indicative of a movement of the shaped X-ray beambeing projected on the object and wherein based on said second data themethod includes using the processor for calculating a plurality ofactive pixels corresponding to a new location of interaction of theshaped X-ray beam on the object; using the processor for calculating atime duration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and using the processor for generating an updated image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration. Optionally, thenew location is associated with an updated first data generated by thegyroscope, and wherein said updated first data is indicative of a newdirection of the shaped X-ray beam being projected on the object.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration ranging between 0.01 ms and 100 ms.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the location is associated with a first datagenerated by the gyroscope, and wherein said first data is indicative ofa direction of the shaped X-ray beam being projected on the object.

In some embodiments, the present specification discloses a system for ahand-held imaging device for scanning an object by projecting a shapedX-ray beam, where the device includes a housing having a centrallongitudinal axis. In some embodiments, the housing includes a firstrotating collimator having a first transmission pattern and a secondrotating collimator having a second transmission pattern, said first andsecond transmission patterns defining said shaped X-ray beam; aplurality of detectors for generating scan data corresponding to aplurality of detected X-ray beams; a gyroscope; an accelerometer; anacquisition system in communication with a speaker, a display and saidplurality of detectors; and a processor in communication with saidgyroscope, said accelerometer and said acquisition system. In someembodiments, the processor is configured for calculating a plurality ofactive pixels corresponding to a location of interaction of the shapedX-ray beam on the object; calculating a time duration, at each of saidplurality of active pixels, for which the shaped X-ray beam is presentover each of said plurality of active pixels; and generating an image,on said display, of the object after correcting the scan data, at eachof said plurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam. Optionally, the first transmission pattern defines a radialposition of said pencil beam while said second transmission patterndefines an azimuthal angle of said pencil beam.

In some embodiments, the first and second collimators rotate in lockstep with each other, and wherein said first collimator rotates at afirst speed while said second collimator rotates at a second speed.Optionally, the second speed is greater than said first speed.

In some embodiments, the first and second collimators are substantiallycircular disks having differing radii.

In some embodiments, the first and second collimators are substantiallycircular disks having same radii.

In some embodiments, the first transmission pattern is a slit extendingin a spirally curved configuration from a point proximate a center ofsaid first collimator to a point proximate a circumference of said firstcollimator, and wherein said second transmission pattern is a slitextending radially from a point proximate a center of said secondcollimator to a point proximate a circumference of said secondcollimator.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a second cuboid culminating in said rearsurface. Optionally, the shaped X-ray beam emerges through an opening ata center of said front surface in a direction substantiallyperpendicular to said front surface. Optionally, the plurality ofdetectors are positioned adjacent to and behind said front surfacesurrounding said opening at the center of said front surface.Optionally, the first collimator is arranged coaxially in front of saidsecond collimator along a central longitudinal axis of said housing, andwherein said first and second collimators are positioned between saidopening of said front surface and an opening of said X-ray tube.

In some embodiments, the present specification discloses a method forscanning an object by projecting a shaped X-ray beam from a hand-heldimaging device. In some embodiments, the device incudes a housingenclosing an X-ray tube that emits the shaped X-ray beam, a rotatingcollimator having a transmission pattern defining said shaped X-raybeam, said rotating collimator supported and partially surrounded by anoscillating shaped cradle, a plurality of detectors for generating scandata corresponding to a plurality of detected X-ray beams, a processorin communication with a gyroscope and an accelerometer, and anacquisition system in communication with a speaker, a display, saidprocessor and said plurality of detectors. In some embodiments, themethod includes using the processor for calculating a plurality ofactive pixels corresponding to a location of interaction of the shapedX-ray beam on the object; using the processor for calculating a timeduration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and using the processor for generating an image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam.

In some embodiments, the hand-held imaging device is swept to scan theobject using a coarse scanning pattern to identify at least one anomaly,with reference to the object, prior to calculating said plurality ofactive pixels, calculating said time duration and generating said image.Optionally, the anomaly is identified based on a change in audible tonegenerated by the speaker. Still optionally, a pitch or frequency of saidaudible tone is proportional to said generated scan data. Optionally,upon identification of said at least one anomaly, the hand-held imagingdevice is swept to scan the object using a fine scanning pattern forcalculating said plurality of active pixels, calculating said timeduration and generating said image.

In some embodiments, the method further includes receiving second databy the processor, wherein said second data is generated by theaccelerometer and is indicative of a movement of the shaped X-ray beambeing projected on the object and wherein based on said second data themethod includes using the processor for calculating a plurality ofactive pixels corresponding to a new location of interaction of theshaped X-ray beam on the object; using the processor for calculating atime duration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and using the processor for generating an updated image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration. Optionally, thenew location is associated with an updated first data generated by thegyroscope, and wherein said updated first data is indicative of a newdirection of the shaped X-ray beam being projected on the object.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration ranging between 0.01 ms and 100 ms.

In some embodiments, the acquisition system sums said detected scan dataover a sampling duration of 1 ms.

In some embodiments, a voltage of the X-ray tube ranges between 30 kVand 100 kV.

In some embodiments, a current of the X-ray tube ranges between 0.1 mAand 5 mA.

In some embodiments, the location is associated with a first datagenerated by the gyroscope, and wherein said first data is indicative ofa direction of the shaped X-ray beam being projected on the object.

In some embodiments, the present specification discloses a system for ahand-held imaging device for scanning an object by projecting a shapedX-ray beam, where the device includes a housing having a centrallongitudinal axis. In some embodiments, the housing includes a rotatingcollimator having a transmission pattern defining said shaped X-raybeam, said rotating collimator supported and partially surrounded by anoscillating shaped cradle; a plurality of detectors for generating scandata corresponding to a plurality of detected X-ray beams; a gyroscope;an accelerometer; an acquisition system in communication with a speaker,a display and said plurality of detectors; and a processor incommunication with said gyroscope, said accelerometer and saidacquisition system. In some embodiments, the processor is configured forcalculating a plurality of active pixels corresponding to a location ofinteraction of the shaped X-ray beam on the object; calculating a timeduration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and generating an image, on said display, of the object aftercorrecting the scan data, at each of said plurality of active pixels,using said time duration.

In some embodiments, the shaped X-ray beam is in the form of a pencilbeam.

In some embodiments, the collimator rotates at a speed ranging between100 to 5000 RPM. In some embodiments, the collimator rotates at a speedof 2000 RPM.

In some embodiments, the rotating collimator causes said shaped X-raybeam to sweep a trajectory in a substantially vertical plane such that afocal spot of said shaped X-ray beam is in a plane of said rotatingcollimator and on a central longitudinal axis of said housing, andwherein said oscillating shaped cradle causes said shaped X-ray beam tosweep left to right, repeatedly, over said substantially vertical plane.

In some embodiments, the collimator is a substantially circular diskhaving a first radius while said shaped cradle is substantiallysemi-circular having a second radius, and wherein said second radius isgreater than said first radius.

In some embodiments, the collimator is a substantially circular diskhaving a radius while said shaped cradle is substantially ‘U’ or ‘C’shaped.

In some embodiments, the transmission pattern is an opening at a pointbetween a center and a circumference of said collimator, and whereinsaid rotating and said oscillating movements together cause said shapedX-ray beam to move in a raster pattern over a two dimensional area ofthe obj ect.

In some embodiments, the housing has an upper surface, a base oppositeand parallel to said upper surface, a front surface, a rear surfaceopposite and parallel to said front surface, a first side and a secondside opposite and parallel to said first side, and wherein said uppersurface has at least one handle. Optionally, the housing is configuredas a first cuboid, bearing said front surface, which tapers along thecentral longitudinal axis into a second cuboid culminating in said rearsurface. Optionally, the shaped X-ray beam emerges through an opening ata center of said front surface in a direction substantiallyperpendicular to said front surface. Still optionally, the plurality ofdetectors are positioned adjacent to and behind said front surfacesurrounding said opening at the center of said front surface. Stilloptionally, respective centers of said collimator and said shaped cradleare substantially coaxial with a central longitudinal axis of saidhousing, and wherein said collimator and said shaped cradle arepositioned between said opening of said front surface and an opening ofsaid X-ray tube.

The aforementioned and other embodiments of the present specificationshall be described in greater depth in the drawings and detaileddescription provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present specificationwill be appreciated, as they become better understood by reference tothe following detailed description when considered in connection withthe accompanying drawings, wherein:

FIG. 1A is a perspective view of a hand-held portable scanning device,in accordance with an embodiment of the present specification;

FIG. 1B is a vertical cross-sectional view of the hand-held portablescanning device of FIG. 1A;

FIG. 1C illustrates the hand-held portable scanning device of thepresent specification projecting an X-ray beam over an object underinspection, in an embodiment;

FIG. 2A is a perspective view of a hand-held portable scanning device,in accordance with another embodiment of the present specification;

FIG. 2B is a vertical cross-sectional view of the hand-held portablescanning device of FIG. 2A;

FIG. 2C illustrates the hand-held portable scanning device of thepresent specification projecting an X-ray beam over an object underinspection, in an embodiment;

FIG. 3A is a perspective view of a hand-held portable scanning device,in accordance with another embodiment of the present specification;

FIG. 3B is a vertical cross-sectional view of the hand-held portablescanning device of FIG. 3A;

FIG. 3C illustrates the hand-held portable scanning device of thepresent specification projecting an X-ray beam over an object underinspection, in an embodiment;

FIG. 3D illustrates a collimator grid fabricated by assembling orarranging a plurality of combs having a plurality of teeth, inaccordance with an embodiment;

FIG. 3E illustrates a sensing module formed by coupling an array ofdetectors to a card with a single signal control and readout cable, inaccordance with an embodiment;

FIG. 3F illustrates a collimator grid coupled to a sensing module, inaccordance with an embodiment;

FIG. 4A is a perspective view of a hand-held portable scanning device,in accordance with yet another embodiment of the present specification;

FIG. 4B is a vertical cross-sectional view of the hand-held portablescanning device of FIG. 4A;

FIG. 4C illustrates first and second collimator disks having first andsecond transmission patterns, respectively, in accordance with anembodiment;

FIG. 4D illustrates various exemplary positions of a moving or sweepingpencil X-ray beam defined by first and second transmission patterns ofthe first and second collimator disks shown in FIG. 4C;

FIG. 4E illustrates a motor driven assembly of first and second gearswhich, in turn, rotate the first and second collimator disks, shown inFIG. 4C;

FIG. 4F illustrates two sets of free running drive wheels or gears usedto support the first and second collimator disks, shown in FIG. 4C;

FIG. 4G illustrates the hand-held portable scanning device of thepresent specification projecting an X-ray beam over an object underinspection, in an embodiment;

FIG. 5A is a perspective view of a hand-held portable scanning device,in accordance with still another embodiment of the presentspecification;

FIG. 5B is a vertical cross-sectional view of the hand-held portablescanning device of FIG. 5A;

FIG. 5C is a front view of a motor driven collimator assembly comprisinga collimator and support or cradle, in accordance with an embodiment;

FIG. 5D is a side view of the motor driven collimator assembly of FIG.1C;

FIG. 5E is a substantially spherical head portion of an X-ray tubepositioned within the collimator assembly, in accordance with anembodiment;

FIG. 5F illustrates the hand-held portable scanning device of thepresent specification projecting an X-ray beam over an object underinspection, in an embodiment;

FIG. 6A is a block diagram illustrating a data acquisition system and aprocessing element in data communication with a plurality of detectors,a collimator motor, an azimuth motor, and a rotary encoder, in anembodiment of the present specification;

FIG. 6B is a block diagram illustrating a data acquisition system and aprocessing element in data communication with a plurality of detectors,a gyroscope and an accelerometer, in an embodiment of the presentspecification; and,

FIG. 7 is a flow chart illustrating exemplary steps of a method ofscanning an object using the hand-held portable device of the presentspecification.

DETAILED DESCRIPTION

In some embodiments, the present specification discloses a system forscanning an object by projecting a shaped X-ray beam from a hand-heldimaging device, where the device includes a housing enclosing an X-raytube that emits the shaped X-ray beam, a plurality of detectors forgenerating scan data, a processor in communication with a gyroscope andan accelerometer, and an acquisition system. In some embodiments, themethod includes using the processor for calculating a plurality ofactive pixels corresponding to a location of interaction of the shapedX-ray beam on the object; using the processor for calculating a timeduration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and using the processor for generating an image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration.

In some embodiments, the shaped X-ray beam is a pencil beam.

In some embodiments, the shaped X-ray beam is a cone beam.

In some embodiments, the shaped X-ray beam is a fan beam.

In some embodiments, the shaped X-ray beam is a single-axis rotatingbeam.

In some embodiments, the shaped X-ray beam is a dual-axis rotating beam.

The present specification is directed towards multiple embodiments. Thefollowing disclosure is provided in order to enable a person havingordinary skill in the art to practice the invention. Language used inthis specification should not be interpreted as a general disavowal ofany one specific embodiment or used to limit the claims beyond themeaning of the terms used therein. The general principles defined hereinmay be applied to other embodiments and applications without departingfrom the spirit and scope of the invention. Also, the terminology andphraseology used is for the purpose of describing exemplary embodimentsand should not be considered limiting. Thus, the present invention is tobe accorded the widest scope encompassing numerous alternatives,modifications and equivalents consistent with the principles andfeatures disclosed. For purpose of clarity, details relating totechnical material that is known in the technical fields related to theinvention have not been described in detail so as not to unnecessarilyobscure the present invention. In the description and claims of theapplication, each of the words “comprise” “include” and “have”, andforms thereof, are not necessarily limited to members in a list withwhich the words may be associated.

Pencil Beam

FIG. 1A illustrates an embodiment of a hand-held portable X-ray basedscanning system 100, also referred to as an imaging system or device,for use in screening objects such as, but not limited to, baggage,containers/boxes, and other similar items for threat materials, items orpeople concealed therein. The system 100 is configured, in oneembodiment, in the form of an enclosure or housing 105 having an uppersurface 110, a base (not visible in FIG. 1A, but opposite, andsubstantially parallel to, the upper surface 110), a front surface 114,a rear surface (not visible in FIG. 1A, but opposite, and parallel to,the front surface 114), a first side 118, and a second side (not visiblein FIG. 1A, but opposite, and parallel to, the first side 118). Inaccordance with one embodiment, the size and weight of system 100 isoptimized for enabling an operator to conveniently hold and maneuver thehousing 105 while scanning an object under inspection. In oneembodiment, housing 105 is in the form of a first cuboid 125 (bearingthe front surface 114) that tapers, along a central longitudinal axis130, into a second cuboid 135 culminating in the rear surface. Inaccordance with an embodiment, a height ‘H’ of the first cuboid 125 isgreater than a height ‘h’ of the second cuboid 135. It should, however,be appreciated that the shape of the housing 105 can be cylindrical,conical, pyramidal or any other suitable shape in various embodiments.Specifically, in one embodiment, housing 105 is in the form of a firstcuboid 125 that attaches, at a back face and along a centrallongitudinal axis 130, to a first trapezoidal prism 118 that tapers and,at its back face, attaches a second trapezoidal prism 135.

At least one handle 112 is provided on, for example, the upper surface110 to allow the operator to hold the housing 105 conveniently in one orboth hands and manipulate the device 100 to point the front surface 114towards and at different regions on the object under inspection. Inalternate embodiments one or more handles are provided on one or moreareas or regions such as the upper surface 110, the base, the first side118 and/or the second side so that single-handed or two-handed operationof device 100 is facilitated, depending on what is easiest for theoperator.

Conventionally, X-rays are generated using a thermionic source ofelectrons, such as a hot tungsten wire in vacuum. The thermionicelectrons are then accelerated in an electric field towards an anode ortarget at a high electrical potential relative to the electron source.Typically the anode is made from a refractory metal of high atomicnumber, such as tungsten or molybdenum. When electrons hit the anode athigh potential, X-rays are created as the electrons lose energy in theanode material. Typically it is through the photoelectric andBremsstrahlung interactions by which the electrons lose their energy andso create X-rays. The net result is a broad spectrum of X-ray energies,from close to zero up to the maximum energy of the acceleratedelectrons.

The principles described above are applicable throughout each of theembodiments described in the present specification and will not berepeated with respect to each embodiment.

Referring now to FIGS. 1A and 1B, the housing 105 comprises an X-raytube 140 whose anode 141, also referred to as a target, emits aspatially localized X-ray beam 145 through an opening 142, also referredto as an aperture. At least one shield 143, formed of an X-rayabsorptive material, such as tungsten or uranium, surrounds and enclosesanode 141 to absorb stray radiation emitted from anode 141. Opening 142,defined through shield 143, is provided with a size and thickness whichenables opening 142 to act as a collimator in forming or shaping andlimiting the X-ray radiation, emitted from anode 141, into a shaped beamof X-rays 145. In one embodiment, X-ray beam 145 is shaped into a pencilbeam.

A cathode and heater filament assembly (enclosed within housing 105) isheld at a substantial potential difference (using a chargeable batteryalso enclosed within the housing 105) with reference to anode 141 by akilovolt power supply (wrapped around at least one tube shielding 143,in one embodiment). This potential difference causes thermionicelectrons freed by the heated cathode (heated using the heater filament)to be directed and drawn to anode 141 at sufficiently high velocity toresult in the generation of X-ray beam 145.

In accordance with an embodiment, shaped X-ray beam 145 emerges throughan opening 144 at the center of front surface 114 of housing 105, in adirection substantially perpendicular to front surface 114. At least oneor a plurality of X-ray backscatter detectors 150, also referred to assensors, are positioned adjacent to and behind front surface 114 suchthat they surround the area or region of emergence of X-ray beam 145 atopening 144 and cover a substantial area of front surface 114 in orderto maximize detected backscatter signal. An embodiment of the presentspecification comprises four sets of detectors 150. In otherembodiments, a different number of detectors 150 may be utilized.

In accordance with an aspect, detectors 150 advantageously comprise highdensity inorganic scintillators (such as NaI, BGO, LYSO, CsI) coupled toa suitable optical readout such as a photomultiplier tube, an array ofsemiconductor photomultipliers or an array of photodiodes. Otherdetector types include inorganic scintillators (such as poly-vinyltoluene) coupled to photomultiplier tubes or room temperaturesemiconductor detectors (such as CdTe, CdZnTe, TlBr, HgI). As will beevident to one skilled in the art, many detector topologies arepossible, such as, but not limited to, square segmented, circularsegmented or annular, while the endeavor is to balance cost againstcomplexity and overall detection efficiency. The detector surfaceadapted to received scattered X-ray radiation is positioned proximatethe front surface 114 of housing 105.

Also, detectors 150 can be operated in a plurality of ways. For example,each detector can be operated in a pulse-counting, energy discriminatingmode to build up an energy spectrum of the interacting X-rays, wherebythese spectra are sampled over short scanning periods to build up a mapof count rate and associated energy spectrum for each scatter sourcepoint location on the surface of the object under inspection. As anexample, assume that the operator is scanning the beam at a rate of 0.2m/second over the surface of the object and the projected X-ray beamwidth at the object is 10 mm. Therefore, in an embodiment, the updaterate is equal to a movement of half the X-ray beam width (5 mm in thiscase) corresponding to a dwell time of (5 mm)/(200 mm/s) = 25 ms. Theenergy distribution in the spectrum is analyzed to find those X-rays ofhigher energy which are more likely to have come from a greater depth inthe object compared to those at lower energy which are more likely tohave come from the surface of the object. It is also possible toseparate out those photons whose energy is higher than the maximumemitted from the X-ray tube since these are either summed events (inwhich more than one scattered X-ray interacted in the detector at thesame time) or are events due to naturally occurring backgroundradiation. In either case, these are used to compensate for artifactsthat would otherwise be present in the signal data.

It should be noted that the maximum energy of the X-rays produced byX-ray tube 140 determines the ability of these X-rays to penetrate intothe object under inspection - that is, the higher the maximum X-rayenergy, the more penetration can be achieved. Similarly, the higher theenergy of the scattered X-ray photon, the more likely it is to escapethrough the object under inspection back to an X-ray detector 150.Therefore, in accordance with an aspect it is desirable to have highX-ray energy to maximize depth of inspection within the object.

To improve signal quality, device 100 of the present specificationmaximizes the number of scattered X-rays that are detected within agiven signal integration or sampling period. The number of scatteredX-rays for a given type of object under inspection is dependent on thenumber of X-rays that are incident on the object under inspectiondirectly from the X-ray source. In the case of a fixed tube voltage, itis the anode current that affects the size of the scattered X-raysignal - that is, the higher the anode current, the greater thescattered signal. Most detection systems, such as the detectors 150, areoperated close to the Gaussian point whereby the variance in the signalis equal to the mean value of the signal. For example, if the meannumber of scattered X-rays reaching the detector in a certain countingperiod were 100, then the variance would be 100 and the standarddeviation would be square root of 100 (=10). Signal-to-noise ratio (SNR)is defined as mean divided by standard deviation, therefore, SNR in thisexample would be 100/10 = 10.

Therefore, in a preferred embodiment, device 100 has high X-ray tubevoltage (to improve penetration performance) and high anode current (toimprove signal-to-noise ratio in the scattered X-ray signal). However,such a combination of factors will result in a device which is likely tobe heavy due to the physical size of the X-ray tube components (toprovide suitable clearance and creepage distance in the high voltagecomponents) and the associated radiation shielding that will be neededto collimate the primary shaped beam and to shield the operator andradiation detectors from stray radiation from the X-ray tube target.Therefore, in various embodiments the tube voltage of the X-ray tube 140ranges between 30 kV and 100 kV with tube currents ranging between 0.1mA and 5 mA.

During operation, as shown in FIG. 1C, shaped X-ray beam 145 interactswith an object 160 under inspection, to produce scattered X-rays 146. Asshown, object 160 conceals therein, an item, person or material 161.Scattered X-rays 146 are detected by the detectors 150 to produce scandata signal whose intensity is related to the effective atomic number(Z) near to the surface of object 160.

Compton scattering describes the interaction of an X-ray photon with anelectron that is generally thought of as being at rest. Here, the angleof the exit X-ray photon is related to the direction of the incomingX-ray photon according to the Compton scattering equation:

$\lambda^{\prime} - \lambda = \frac{h}{m_{e}c}\left( {1 - \cos(\theta)} \right)$

where λ = incident photon energy, λ′ = exit photon energy, me = mass ofthe electron and θ = angle between incident and exit photon directions.Thus, the energy of the scattered X-ray is always less than the incidentX-ray, the energy being dependent on both the scattering angle and theincident X-ray photon energy.

The above principles related to Compton scattering described here areapplicable throughout each of the embodiments described in the presentspecification and will not be repeated with respect to each embodiment.

Fan Beam

FIG. 2A illustrates another embodiment of a hand-held portable X-raybased scanning system 200, also referred to as an imaging system ordevice, for use in screening objects such as, but not limited to,baggage, containers/boxes, and other items for threat materials, itemsor people concealed therein. In embodiments, components of system 200,such as - a housing 205, an upper surface 210, a base, a handle 212, afront surface 214, a rear surface, a first side 218, a second side, afirst cuboid 225, a central longitudinal axis 230, and a second cuboid(or trapezoidal prism) 235 - are configured similar to correspondingcomponents described above in context of FIG. 1A. These components, andthe associated variations, are not described herein as they have beendescribed in detail above.

Referring now to FIGS. 2A and 2B, housing 205 comprises an X-ray tube240 whose anode 241, also referred to as a target, emits a spatiallylocalized X-ray beam 245 through an opening 242, also referred to as anaperture. A shield 243, formed of an X-ray absorptive material, such astungsten or uranium, surrounds anode 241 so as to absorb stray radiationemitted from anode 241. Opening 242 is provided with a size andthickness which enables opening 242 to act as a collimator in forming orshaping and limiting the X-ray radiation, emitted from anode 241, into ashaped beam of X-rays 245. In one embodiment, X-ray beam 245 is fanshaped.

A cathode and heater filament assembly (not shown) may be configured,similar to embodiments described in above relation to the pencil beamembodiment. Similarly, energy of the X-rays and signal quality can bemaintained in a manner described above in context of the pencil beamembodiments.

A plurality of collimator vanes, blades, fins or plates 255 arepositioned in front of detectors 250 and behind front surface 214,resulting in the formation of a plurality of collimation elements 256between adjacent collimator vanes 255. In one embodiment, the planes ofthe plurality of collimator vanes 255 are arranged or configured in adirection substantially perpendicular to the orientation of shaped X-raybeam 245 (that is, to the plane of fan beam 245) or substantiallyperpendicular to the front surface of the housing. In some embodiments,plurality of collimator vanes 255 are arranged in a parallelconfiguration, wherein planes of vanes 255 are substantially parallel toeach other, such that a vertical dimension, such as height, of avertical region is viewed through collimators 255 to be of the same sizeas the extent or height ‘H’ of front surface 214. In some embodiments,collimator vanes 255 are alternatively arranged in a focusedconfiguration, wherein the planes of vanes 255 together form a divergingor converging orientation, such that collimator vanes 255 view either asmaller or larger of the vertical dimension, such as height, of thevertical region than the extent or the height ‘H’ of front surface 214.

In various embodiments, detectors 250 are arranged behind collimatorvanes 255 such that at least one of detectors 250 is present percollimation element 256 in order to create a one-dimensional linearimage.

During operation, as shown in FIG. 2C, shaped X-ray beam 245 interactswith an object 260 under inspection, to produce scattered X-rays 246. Asshown, object 260 conceals therein, an item, person or material 261.Scattered X-rays 246 are collimated by the plurality of collimator vanes255 and are then detected by detectors 250 to produce scan data signalwhose intensity is related to the effective atomic number (Z) near tothe surface of object 260. In accordance with an embodiment, eachdetector 250 maps to a specific focus area (of the object 260) which isdefined by a width of X-ray fan beam 245 and an acceptance angle of theindividual collimator vanes 255.

Cone Beam

FIG. 3A illustrates another embodiment of a hand-held portable X-raybased scanning system 300, also referred to as an imaging system ordevice, for use in screening objects such as, but not limited to,baggage, containers/boxes, and other similar items for threat materials,items or people concealed therein. In embodiments, components of system300, such as - a housing 305, an upper surface 310, a base, a handle312, a front surface 314, a rear surface, a first side 318, a secondside, a first cuboid 325, a central longitudinal axis 330, and a secondcuboid (or trapezoidal prism) 335 - are configured similar tocorresponding components described above in context of FIG. 1A. Thesecomponents, and associated variations, are not described herein as theyhave been described in detail above.

Referring now to FIGS. 3A and 3B, housing 305 comprises an X-ray tube340 whose anode 341, also referred to as a target, emits a spatiallylocalized X-ray beam 345 through an opening 342, also referred to as anaperture. Housing 305 may include corresponding components such as ashield 343, configured in a manner disclosed above in context of FIGS.1A and 1B. In one embodiment, X-ray beam 345 is cone shaped.

A cathode and heater filament assembly may be configured, similar toembodiments described in above relation to the pencil beam embodiment.

In accordance with an embodiment, shaped X-ray beam 345 emerges throughan opening 344 at the center of front surface 314, in a directionsubstantially perpendicular to front surface 314. A plurality of X-raybackscatter detectors 350 are configured and operated similar todetectors 150 already described in context of FIGS. 1A and 1B. As shownin FIG. 3E, in accordance with an embodiment, an array of ‘m’ rows x ‘n’columns of detectors 350 are arranged onto a modular daughter card 351with a single signal control and readout cable 352 to form a sensingmodule 353.

Similarly, the energy of the X-rays and signal quality can be maintainedin a manner described above in context of the pencil beam embodiments.

Referring now to FIGS. 3A, 3D through 3F, in accordance with anembodiment of the present specification, a collimator grid 355 ispositioned in front of detectors 350 and behind front surface 314.Collimator grid 355 comprises a plurality of combs 365 a, 365 b, made ofa suitable attenuating material (such as tungsten, molybdenum or steel),each of plurality of combs 365 a, 365 b including a plurality of teeth370 a, 370 b. In accordance with an embodiment, plurality of combs 365a, 365 b are assembled or arranged such that teeth 370 a of a first setof combs 365 a in a first direction 371a interlock with teeth 370 b of asecond set of combs 365 b in a second direction 371b to thereby generatethe collimator grid 355 having a plurality of grid collimators orcollimator elements 374. In one embodiment, second direction 371b isgenerally or approximately traverse or orthogonal to first direction371a. In accordance with an embodiment, the first set comprises ‘m’number of combs 365 a while the second set comprises ‘n’ number of combs365 b to generate a collimator grid 355 that has ‘m x n’ matrix ofsubstantially rectangular grid collimators 374 at top surface 375.

In one embodiment, the planes of teeth 370 a, 370 b, forming the gridcollimators or collimator elements 374, are in a direction substantiallyparallel to the orientation of the shaped X-ray beam 345 (that is, coneshaped beam 345) or perpendicular to the front surface of the housing.In some embodiments, the plurality of grid collimators or collimatorelements 374 are arranged in a parallel configuration, wherein theplanes of teeth 370 a, 370 b are substantially parallel to each other,such that a vertical dimension, such as height, of a vertical region isviewed through the collimators 374 to be of the same size as the extentor height ‘H’ of front surface 314. In some embodiments, the pluralityof grid collimators or collimator elements 374 are alternativelyarranged in a focused configuration, wherein the planes of teeth 370 a,370 b together form a diverging or converging orientation, such that thecollimator elements 374 view either a smaller or larger of the verticaldimension, such as height, of the vertical region than the extent or theheight ‘H’ of front surface 314. In still various embodiments, theplurality of grid collimators or collimator elements 374 is arranged ina combination of parallel and focused configurations.

In various embodiments, detectors 350 are arranged behind theinterlocking collimator structure or collimator grid 355 such that atleast one of detectors 350 is present per collimator element or gridcollimator 374 in order to create a two-dimensional scan image. As shownin FIG. 3F, collimator grid 355 is coupled to sensing module 353(comprising the detector module 350 coupled to the daughter card 351with the signal control and readout cable 352) such that the array of ‘mx n’ detectors 350 are positioned behind grid 355.

During operation, as shown in FIG. 3C, shaped X-ray beam 345 interactswith an object 360 under inspection to produce scattered X-rays 346. Asshown, object 360 conceals therein, an item or material 361. ScatteredX-rays 346 is collimated by the plurality of grid collimators orcollimator elements 374 and is then detected by the detectors 350 toproduce scan data signal whose intensity is related to the effectiveatomic number (Z) near to the surface of object 360. In accordance withan embodiment, each detector 350 maps to a specific focus area (of theobject 360) which is defined by a solid angle of X-ray cone beam 345 andan acceptance angle of the individual collimator elements or gridcollimators 374.

Conventional backscatter imaging systems typically use a tightlycollimated pencil beam of X-rays and an un-collimated large areadetector (referred to as “pencil beam geometry”) compared to the use ofthe collimated cone-shaped beam of X-rays and collimated detectors(referred to as “cone beam geometry”) in accordance with an aspect ofthe present specification. With reference to FIG. 3A, the handhelddevice of the present specification has, in one embodiment, an outerdiameter of 192 mm (considering a circular cross-section of the housing105) of front surface 314 and is located at a distance of 100 mm fromthe object under inspection. Detector element 350 is, in an embodiment,3 mm × 3 mm with the X-ray source (X-ray tube 140) located a further 30mm behind detector array 350 to provide room for radiation shieldingaround the source. In this embodiment, a total of 4096 detector elementsare employed (to create a 64 pixel by 64 pixel image) with an equivalentdwell time of 500 microseconds for pencil beam geometry.

To establish the relative efficiency of the pencil beam versus cone beamconfiguration, it is useful to calculate the relative solid angles ofthe whole detector face (pencil beam) and of a single detector to theequivalent inspection area as scanned by the pencil beam (for the conebeam case). This calculation shows that the solid angle for thecollimated detector (used in cone beam geometry) is 290 times smallerthan for the whole detector face (used in pencil beam geometry).

Taking the assumed pencil beam dwell time of 500 microseconds andmultiplying by the number of pixel locations to form an image (4096 inthis case) yields an estimated image formation time in pencil beamgeometry of 2 seconds. The calculation in the case of the cone beamgeometry of the present specification suggests that the dwell timeshould be 290 times longer than for the pencil beam case to achieveequivalent image statistics, but with a single exposure since all pixeldata is collected in parallel. Also, in the case of the cone beamgeometry, the image exposure time is more than 50% less than anequivalent pencil beam. This yields an image exposure time in a range of0.03 seconds 0.1 seconds. Therefore, near real-time two-dimensionalimage inspection is possible using Compton backscatter inspection in thecone beam geometry of the present specification.

Single-Axis Rotating Beam

FIG. 4A illustrates an embodiment of a hand-held portable X-ray basedscanning system 400, also referred to as an imaging system or device,for use in screening objects such as, but not limited to, baggage,containers/boxes, and other similar items for threat materials, items orpeople concealed therein. In embodiments, components of system 400, suchas - a housing 405, an upper surface 410, a base, a handle 412, a frontsurface 414, a rear surface, a first side 418, a second side, a firstcuboid 425, a central longitudinal axis 430, and a second cuboid (ortrapezoidal prism) 435 - are configured similar to correspondingcomponents described above in context of FIG. 1A. These components, andassociated variations, are not described herein as they have beendescribed in detail above.

Referring now to FIGS. 4A and 4B, housing 405 comprises an X-ray tube440 whose anode 441, also referred to as a target, emits a spatiallylocalized X-ray beam 445 a through an opening 442, also referred to asan aperture. A shield 443, formed of an X-ray absorptive material, suchas tungsten or uranium, surrounds anode 441 to absorb stray radiationemitted from anode 441. Opening 442 is defined through a highlyabsorbing block or material (typically tungsten, steel and/or lead) tolimit the X-ray radiation, emitted from anode 441, and allow the X-rayradiation to emanate from X-ray tube 440 in the form of beam 445 a ofX-rays. A cathode and heater filament assembly may be configured,similar to embodiments described in above relation to the pencil beamembodiment.

In accordance with an embodiment of the present specification, X-raybeam 445 a is collimated by a collimator assembly 470, enclosed withinhousing 405, to generate a shaped X-ray beam 445 b. In one embodiment,X-ray beam 445 b is shaped into a pencil beam. In accordance with anembodiment, shaped X-ray beam 445 b emerges through an opening 444 atthe center of front surface 414, in a direction substantiallyperpendicular to front surface 414. A plurality of X-ray backscatterdetectors 450 are positioned adjacent to and behind front surface 414such that they surround the area or region of emergence of X-ray beam445 b at opening 444 and cover a substantial area of front surface 414in order to maximize detected backscatter signal. An embodiment of thepresent specification comprises four sets of detectors 450, alsoreferred to as sensors.

An embodiment of collimator assembly 470 comprises a first collimator472, also referred to as a first limiting element, arranged coaxially infront of a second collimator 474, also referred to as a second limitingelement. In one embodiment first and second collimators 472, 474 arepositioned between openings 443 and 444 such that collimator assembly470 defines, shapes, or forms X-ray beam 445 a into the shaped X-raybeam 445 b.

Referring now to FIGS. 4A through 4F, in one embodiment, first andsecond collimators 472, 474 are substantially circular disks havingdiffering or same radii. In an embodiment, the respective centers of thefirst and second collimators 472, 474 are coaxial with the centrallongitudinal axis 430 of housing 405. First collimator 472 has a firsttransmission pattern in the form of a through slit 473 extending in aspirally curved configuration from a point proximate center 475 to apoint proximate the circumference of element 472. Second collimator 474has a second transmission pattern in the form of through slit 477extending radially from a point proximate center 476 to a pointproximate the circumference of element 474. Thus, when two collimators472, 474 are concurrently rotating, the respective first and secondtransmission patterns or slits 473, 477 generate or define the scanningX-ray pencil beam 445 b across the surface of the object underinspection.

In accordance with an embodiment, the first transmission pattern 473defines a radial position of pencil beam 445 b while the secondtransmission pattern 477 defines an azimuthal angle of pencil beam 445b. For example, as shown in FIG. 4D, when collimators 472, 474 (the twocollimator disks 472, 474 are visible as a single disk since they areshown overlapping each other in FIG. 4D) are rotated relative to eachother the position of pencil beam 445 b moves or sweeps from a position480 a at the circumference to a position 480 d at the coaxial centers475, 476 (of the collimators 472, 474) through intermediate positions480 b and 480 c.

FIG. 4E illustrates a motor 485 driving the first and second collimators472, 474 using a first and a second gear or drive wheels 486, 487respectively. As would be evident to those of ordinary skill in the art,gears 486, 487, also referred to as drive wheels, engage with matinggear teeth fabricated on the respective circumferences of two collimatordisks 472, 474. In accordance with an embodiment, first and second gears486, 487 rotate the collimator disks 472, 474 such that two collimators472, 474 are in lock step with each other but rotate at varying speedsto form beam 445 a into the shaped X-ray beam 445 b. In one embodiment,collimator disk 474 rotates more quickly compared to the speed ofrotation of collimator disk 472. In one embodiment, collimator disk 472rotates more quickly compared to the speed of rotation of collimatordisk 474. In one embodiment, the drive wheel or gears 486, 487 affixedto a common spindle (not visible) are driven by motor 485 to rotatecollimator disks 472, 474 while two sets of additional free runningwheels 488, 489 (not driven by motor 485), shown in FIG. 4F, supportcollimator disks 472, 474 to maintain their position or orientationrelative to X-ray tube 440 (or opening 442).

A plurality of X-ray backscatter detectors 450 are configured andoperated similar to detectors 150 already described in context of FIGS.1A and 1B. Similarly, energy of the X-rays and signal quality can bemaintained in a manner described earlier in context of the pencil beamembodiments.

During operation, as shown in FIG. 4G, shaped X-ray beam 445 b interactswith an object 460 under inspection to produce scattered X-rays 446. Asshown, object 460 conceals therein, an item or material 461. ScatteredX-rays 446 are then detected by detectors 450 to produce scan datasignal whose intensity is related to the effective atomic number (Z)near to the surface of object 460. Any one or more of the aforementionedcollimation systems can be combined with this single-axis rotating beamembodiment to effectively detect scattered X-rays.

Dual-Axis Rotating Beam

FIG. 5A illustrates another embodiment of a hand-held portable X-raybased scanning system 500, also referred to as an imaging system ordevice, for use in screening objects such as, but not limited to,baggage, containers/boxes, and other similar items for threat materials,items or people concealed therein. In embodiments, components of system500, such as - a housing 505, an upper surface 510, a base, a handle512, a front surface 514, a rear surface, a first side 518, a secondside, a first cuboid 525, a central longitudinal axis 530, and a secondcuboid (or trapezoidal prism) 535 - are configured similar tocorresponding components described above in context of FIG. 1A. Thesecomponents, and associated variations, are not described here to avoidrepetition.

Referring now to FIGS. 5A and 5B, housing 505 comprises an X-ray tube540 (shown separated out from housing 505 in FIG. 5B) whose anode 541,also referred to as a target, emits a spatially localized X-ray beam 545a through an opening 542, also referred to as an aperture. A shield 543,formed of an X-ray absorptive material, such as tungsten, steel, lead oruranium, is disposed to surround and enclose anode 541 to absorb strayradiation emitted from anode 541. Further, the anode is surrounded by ahighly absorbing block or material 593 (typically tungsten, steel and/orlead) through which opening 542 is defined. In an embodiment, opening542 is a cone beam collimator slot and defines the overall area forX-ray emission, emitted from anode 541 in the form of beam 545 a, withthe moving collimator parts described below. In some embodiments,opening 542 is shaped so that X-ray beam 545 a emanates as a cone beam.Also, in an embodiment, the head portion of X-ray tube 540, comprisingopening 542, is shaped in a substantially spherical form. A cathode andheater filament assembly (not shown) may be configured, similar toembodiments described in above relation to the pencil beam embodiment.

An embodiment of collimator assembly 570 comprises a collimator 572,also referred to as a limiting element, partially surrounded by a shapedsupport or cradle element 574. In various embodiments, support or cradle574 has a substantially semi-circular, ‘U’ or ‘C’ shape. In anembodiment, collimator 572 is a circular disk having a first radius. Inone embodiment, where cradle 574 is substantially semi-circular shaped,it has a second radius, greater than the first radius, so that cradle574 partially encompasses collimator 572. In accordance with anembodiment collimator 572 and cradle 574 are positioned between openings543 and 544 such that a movement of collimator assembly 570 defines,shapes or forms X-ray beam 545 a into pencil shaped X-ray beam 545 b.

Referring now to FIGS. 5A through 5E, in one embodiment, the respectivecenters of collimator 572 and cradle 574 are substantially coaxial withcentral longitudinal axis 530 of housing 505. Collimator 572 has atransmission pattern in the form of a through opening 573 at a pointbetween the center and the circumference of element 572. Collimator 572is rotatable, about central longitudinal axis 530, through a bearing 582supported by shaped cradle 574. Cradle 574 is fixed to pivoting mountsthat allow cradle 572 to be oscillated about a vertical axis 532. Inaccordance with an aspect of the present specification, a motor 585rotates or spins collimator 572, at a speed, about central longitudinalaxis 530 while the supporting element or cradle 574 vibrates oroscillates, from side to side, about vertical axis 532 thereby causingthe rotating or spinning collimator 572 to also vibrate or oscillate. Invarious embodiments, collimator 572 rotates at a speed ranging between100 to 5000 RPM. In one embodiment, collimator 572 speed is 2000 RPM.

Rotating collimator 572 defines pencil beam 545 b that sweeps atrajectory in a substantially vertical plane where the X-ray focal spotis in the plane of collimator 572 and on longitudinal axis 530 ofbearing 582. The vibratory or oscillatory movement of cradle 574 andtherefore that of collimator 572 causes pencil beam 545 b to sweep overthe substantially vertical plane moving from left to right and backagain. The combined effect of the rotatory or spinning and oscillatoryor vibratory movement of the collimator assembly 570 is one where pencilbeam 545 b moves in a raster pattern over a two dimensional area of theobject under inspection. FIG. 5E shows X-ray tube 540 positioned withinthe moving collimator assembly 570 so that the substantially sphericalshaped head portion 590 of X-ray tube 540, comprising opening 542, androtating collimator 572 (supported by cradle 574) enable tight radiationcollimation as X-ray beam 545 b is scanned. The substantially sphericalshaped head portion 590 of X-ray tube 540 allows the rotating androcking or oscillating collimator 572 to efficiently move around head590 with minimum radiation leakage.

A plurality of X-ray backscatter detectors 550 are configured andoperated similar to detectors 150 already described in context of FIGS.1A and 1B. Similarly, energy of the X-rays and signal quality can bemaintained in a manner described earlier in context of the pencil beamembodiments.

In one embodiment, detectors 550 are scintillator based detector arrayswith light guide readout to photomultiplier tubes.

During operation, as shown in FIG. 5F, shaped X-ray beam 545 b interactswith an object 560 under inspection to produce scattered X-rays 546. Asshown, object 560 conceals therein, an item or material 561. ScatteredX-rays 546 are then detected by detectors 550 to produce scan datasignal whose intensity is related to the effective atomic number (Z)near to the surface of object 560. Any one or a combination of thecollimation systems disclosed above may be combined with thisembodiment.

The position of the collimators is used to accurately correct images.Referring to FIG. 6A, a plurality of sensors 640 (corresponding to atleast one of the detectors or detector systems mentioned in theembodiments above) is used to acquire data and communicate that data toa data acquisition system (DAQ) 610. DAQ 610, in turn, controls motordrivers responsible for creating collimator motion. Such motors includean azimuth motor 675 and a collimator motor 670. Rotary encoders 680monitor the absolute position of the collimators and supply thatinformation to DAQ 610 which, in turn, uses it to correct an acquiredimage based upon such position data.

As shown in FIG. 6B, in another embodiment, scan data 605 produced byplurality of detectors 645 (corresponding to at least one of thedetectors or detector systems mentioned in the embodiments above) isaccumulated into DAQ 610 wherein scan data 605 is summed withinappropriate or optimal sampling time slots, time bins, or time periods.It should be appreciated that the shorter the sampling time period thenoisier is the collected scan data but the more accurate or focused itis in terms of spatial location. In various embodiments scan data 605sampling time slots, time bins, or time periods vary between 0.01 ms and100 ms. In one embodiment, scan data 605 sampling time slot or timeperiod is of 1 ms duration. A processing element 650, such as amicroprocessor or a digital signal processor (DSP), is in datacommunication with DAQ 610 to perform a plurality of analyses orcalculations using at least scan data 605. In one embodiment, scan data605 is analyzed by comparing a mean scan signal level calculated overone or more temporal sampling periods with a background reference level.The bigger the difference between the sampled signal and the backgroundlevel, the more substantial is the scattering object.

In accordance with an embodiment where a fan beam is utilized, theanalysis is computed behind each of the plurality of collimator vanes255 (FIGS. 2A, 2B), independently, in order to enable spatiallocalization and detection of even small anomalies. In furtherembodiments, to improve signal-to-noise ratio, the intensity of detectedscatter signal 605 is estimated over all detectors 645 (corresponding toat least one of the detectors or detector systems mentioned in theembodiments above) by calculating a weighted sum of the pixel based andtotal signal data analysis.

In accordance with an aspect of the present specification, for each ofthe embodiments (illustrated in FIGS. 6A and 6B) disclosed above, thedetected scatter scan data 605 is utilized to generate an alarm orfeedback for the operator. In various embodiments the alarm or feedbackis in the form of an audible tone and/or a scan image of the objectunder inspection. Accordingly, detected scatter scan data 605 isconverted, using a speaker 615, into an audible tone or alarm, the pitchor frequency of which, in one embodiment, is directly proportional tothe scatter signal. For example, speaker 615 emits a background tone atabout 100 Hz with an average signal of 1000 detected scatter X-raysproducing a frequency of about 400 Hz. Thus, a scattering object whichgenerates a signal of 500 detected scatter X-rays would produce a toneat about 250 Hz. It will be appreciated by one of ordinary skill in theart that alternative mapping between detected scatter signal and audibletone or alarm can be envisioned, such as one which provides anexponential increase in tone, pitch or frequency to provide greatercontrast for low scattering objects than for high scattering ones.

The probability of an X-ray photon interacting with the object underinspection depends strongly on the atomic number of the object - thatis, the higher the atomic number the higher the probability ofinteraction. Similarly, the probability of absorbing a Compton scatteredX-ray also depends strongly on the atomic number of the object underinspection. Therefore, it is known by those skilled in the art that theCompton backscatter signal is highest for low atomic number materialssuch as organic materials and people and is smallest for high atomicnumber materials such as steel and lead.

Additionally or alternatively, the scan image of the object underinspection is displayed on at least one display 620. A visual feedback,such as the scan image, is advantageous to enable the operator to noticesubtle differences between one scattering object and another since thehuman visual system has a natural ability at identifying shapes andassociating these shapes with specific threats (such as a gun or aknife). Referring to FIG. 6B, in order to form the scan image, anembodiment of the present specification includes a 3D gyroscope 625and/or a 3D accelerometer 630 within the respective housings. 3Dgyroscope 625 is used to track a first data stream indicative of anabsolute position or pointing direction of the X-ray beam or hand-helddevice in 3D space, while 3D accelerometer 630 tracks a second datastream indicative of rapid relative movements of the X-ray beam in 3Dspace. In accordance with an embodiment, the first and second datastreams are input into and combined by processing element 650 togenerate position or coordinates 640 of the X-ray beam at all timesduring scanning operation, even in response to rapid movement of thebeam or hand-held device (in embodiments described above) by theoperator.

According to an aspect of the present specification, each position orcoordinate of the X-ray beam in 3D space has associated plurality ofactive pixels that correspond to the particular spatial location, on theobject under inspection, where the X-ray beam is interacting. Theseactive pixels are located within a matrix of other potentially activepixels which together constitute an image. In a practical scenario, itis reasonable to assume that the operator will sweep the X-ray beam overthe object more than once causing multiple scan frames to contribute toa pixel in the image. Therefore, in order to ensure a quantitativeimage, the brightness or scan data of each pixel is corrected by thetotal X-ray beam dwell time at that pixel location. This dwell time iscalculated over all periods that the X-ray beam is present over eachactive pixel.

The number of X-rays reaching the object under inspection is defined bythe X-ray beam collimator aperture and beam divergence. The area of theobject under inspection that is covered by the X-ray beam is thendetermined by the distance of the X-ray source from the object underinspection - that is, the larger the distance the larger the area of theobject covered by the X-ray beam. The number of scattered X-rays thatreturn to the detector is inversely proportional to the distance betweenthe object under inspection and the detector array. Thus, in oneoperating condition, the hand-held device of the present specificationas described in various embodiments above is held close to the objectunder inspection, so that the area of the object irradiated by the X-raybeam is small and the fraction of the scattered signal collected by thedetector is high.

FIG. 7 is a flow chart illustrating a plurality of exemplary steps of amethod of scanning an object using an X-ray beam projected by thehand-held portable device of the present specification. At 705, anoperator first sweeps the X-ray beam onto the object using a coarsescanning pattern during which a change in audible tone is used as theprimary feedback to identify anomalies with reference to the object. Thecoarse scanning pattern, in one embodiment, refers to a fairly quickscanning or sweeping movement of the X-ray beam over the surface of theobject, referred to as the general scanning area, where the coarsescanning pattern is defined as having a first density of X-ray coverageover the general scanning area. If no anomaly is identified, at 710,then the scan of the object is stopped, at 712, and a new scan sessionfor another object can begin, if required. However, if an anomaly isidentified, at 710, the operator then proceeds to make fine scanningpatterns or relatively slower movements of the X-ray beam around theanomalous area, at 715, where the fine scanning pattern is defined ashaving a second density of X-ray coverage over the anomalous area. Itshould be appreciated that the anomalous area is smaller than, butpositioned within, the general scanning area. It should also beappreciated that the second density (associated with the fine scanningpattern) is greater than the first density (associated with the coarsescanning pattern).

On initiating the fine sweep scanning of the object, the followingstasks are performed: at 716, data is received from a 3D gyroscoperepresenting a direction of pointing of the X-ray beam projected ontothe object; at 717 a plurality of active pixels corresponding to thedirection of the X-ray beam are calculated; at 718, a dwell time of theX-ray beam at each of the active pixels is calculated; and at 719, ascan image after correcting the scan data signal is generated, at eachof the active pixels, using the dwell time. At 720, data from a 3Daccelerometer is obtained to check if there is a movement of the X-raybeam relative to the direction of the X-ray beam obtained at 716. Ifthere is no movement of the X-ray beam detected, at 723, then the steps717 to 720 are repeated (till a movement of the X-ray beam is detected).

However, if a movement of the X-ray beam is detected, at 723, then thefollowing tasks are performed: at 725, data is received from the 3Dgyroscope representing a new direction of the X-ray beam due to themovement of the X-ray beam; at 726, a plurality of active new pixelscorresponding to the new direction of the X-ray beam are calculated; at727, a dwell time of the X-ray beam at each of the active new pixels iscalculated; and at 728, an updated scan image is generated afterapplying the dwell time correction to the scan data signal at eachactive pixel.

At 730, data from the 3D accelerometer is obtained again to check ifthere is a continued movement of the X-ray beam. If it is determined at733 that the X-ray beam is still moving or being swept over the object,then steps 725 to 730 are repeated (till the X-ray beam sweepingmovement stops). However, in case there is no detected movement of theprojected X-ray beam at 733, then at 735 a check is performed todetermine whether the scanning has to be stopped (and therefore, move to740) or another scanning session or event should begin from 705 onwards.The scan image generated at 719 and/or 728 is visually analyzed by theoperator to determine further features of the anomaly and declare theanomaly as benign or threat.

In various embodiments of the present specification, the hand-helddevice of the present specification, such as those in embodimentsdescribed above, includes a laser-beam range finder or any othersuitable optical sensor beam, known to persons of ordinary skill in theart, is used to propagate an optical, visible light or laser beam alongthe central path of the X-ray beam (for example, by deflecting a laserbeam using a thin gold coated Mylar film reflector in the X-ray beampath). The directed optical or laser beam is used to calculate thedistance of the hand-held device from the object under inspection sothat the surface of the object can be reconstructed in three-dimensional(3D) space (using the measured distance to the surface of the objecttaken in combination with the gyroscope and/or accelerometer data) inorder to create an X-ray image that wraps around the three-dimensionalsurface of the object under inspection. Such a three-dimensional viewcan help the image interpreter or operator to better identify orestimate the exact location of the anomaly or threat object, area orregion.

The above examples are merely illustrative of the many applications ofthe system of present specification. Although only a few embodiments ofthe present invention have been described herein, it should beunderstood that the present invention might be embodied in many otherspecific forms without departing from the spirit or scope of theinvention. Therefore, the present examples and embodiments are to beconsidered as illustrative and not restrictive, and the invention may bemodified within the scope of the appended claims.

We claim:
 1. A method of scanning an object by projecting a shaped X-raybeam from a hand-held imaging device, said device comprising a housingenclosing an X-ray tube that emits the shaped X-ray beam, a plurality ofdetectors for generating scan data corresponding to a plurality ofdetected X-ray beams scattered from the object, a processor incommunication with a gyroscope and an accelerometer, and an acquisitionsystem in communication with a speaker, a display, said processor andsaid plurality of detectors, the method comprising: using the processorfor calculating a plurality of active pixels corresponding to a locationof interaction of the shaped X-ray beam on the object; using theprocessor for calculating a time duration, at each of said plurality ofactive pixels, for which the shaped X-ray beam is present over each ofsaid plurality of active pixels; and using the processor to generate animage, on said display, of the object after correcting the scan data, ateach of said plurality of active pixels, using said time duration. 2.The method of claim 1, wherein said shaped X-ray beam is in the form ofat least one of a pencil beam, a fan beam, a cone beam, a single axisrotating beam, and a double axis rotating beam.
 3. The method of claim1, wherein the hand-held imaging device is swept to scan the objectusing a coarse scanning pattern to identify at least one anomaly, withreference to the object, prior to calculating said plurality of activepixels, calculating said time duration and generating said image.
 4. Themethod of claim 3, wherein said at least one anomaly is identified basedon a change in audible tone generated by the speaker.
 5. The method ofclaim 4, wherein the processor and speaker are adapted to generate saidaudible tone such that a pitch or frequency of said audible tone variesin proportion to said scan data.
 6. The method of claim 3, wherein uponidentification of said at least one anomaly, the hand-held imagingdevice is swept to scan the object using a fine scanning pattern forcalculating said plurality of active pixels, calculating said timeduration and generating said image.
 7. The method of claim 1, furthercomprising receiving second data by the processor, wherein said seconddata is generated by the accelerometer and is indicative of a movementof the shaped X-ray beam being projected on the object and wherein basedon said second data: using the processor for calculating a plurality ofactive pixels corresponding to a new location of interaction of theshaped X-ray beam on the object; using the processor for calculating atime duration, at each of said plurality of active pixels, for which theshaped X-ray beam is present over each of said plurality of activepixels; and using the processor for generating an updated image, on saiddisplay, of the object after correcting the scan data, at each of saidplurality of active pixels, using said time duration.
 8. The method ofclaim 7, wherein said new location is associated with an updated firstdata generated by the gyroscope, and wherein said updated first data isindicative of a new direction of the shaped X-ray beam being projectedon the object.
 9. The method of claim 1, wherein the acquisition systemsums said detected scan data over a sampling duration ranging between0.01 ms and 100 ms.
 10. The method of claim 1, wherein the acquisitionsystem sums said detected scan data over a sampling duration of 1 ms.11. The method of claim 1, wherein a voltage of the X-ray tube rangesbetween 30 kV and 100 kV.
 12. The method of claim 1, wherein a currentof the X-ray tube ranges between 0.1 mA and 5 mA.
 13. The method ofclaim 1, wherein said location is associated with a first data generatedby the gyroscope, and wherein said first data is indicative of adirection of the shaped X-ray beam being projected on the object.
 14. Ahand-held imaging device for scanning an object by projecting a shapedX-ray beam, the device comprising: a housing having a centrallongitudinal axis and comprising: a plurality of detectors forgenerating scan data corresponding to a plurality of detected X-raybeams scattered from the object; a gyroscope; an accelerometer; anacquisition system in communication with a display and said plurality ofdetectors; and a processor in communication with said gyroscope, saidaccelerometer and said acquisition system, wherein said processor isconfigured for: calculating a plurality of active pixels correspondingto a location of interaction of the shaped X-ray beam on the object;calculating a time duration, at each of said plurality of active pixels,for which the shaped X-ray beam is present over each of said pluralityof active pixels; and generating an image, on said display, of theobject after correcting the scan data, at each of said plurality ofactive pixels, using said time duration.
 15. The device of claim 14,wherein said shaped X-ray beam is in the form of at least one of apencil beam, a fan beam, a cone beam, a single axis rotating beam, and adouble axis rotating beam.
 16. The device of claim 14, wherein saidhousing has an upper surface, a base opposite and parallel to said uppersurface, a front surface, a rear surface opposite and parallel to saidfront surface, a first side and a second side opposite and parallel tosaid first side, and wherein said upper surface has at least one handle.17. The device of claim 16, wherein said housing is configured as afirst cuboid, bearing said front surface, which tapers along the centrallongitudinal axis into a trapezoidal prism culminating in said rearsurface.
 18. The device of claim 16, wherein said shaped X-ray beamemerges through an opening at a center of said front surface in adirection substantially perpendicular to said front surface.
 19. Thedevice of claim 18, wherein said plurality of detectors are positionedadjacent to and behind said front surface surrounding said opening atthe center of said front surface.
 20. The device of claim 14, furthercomprising a speaker, wherein said processor and speaker are adapted togenerate an audible tone such that a pitch or frequency of said audibletone varies in proportion to said scan data.